Colorectal cancer in Asians: a demographic and anatomic survey in Malaysian patients undergoing colonoscopy

Background: Colorectal cancer is one of the most common forms of gastrointestinal cancer in the world today. In the Asia-Pacific area, it is the fastest emerging gastrointestinal cancer. Aim: To determine the basic demographic features of patients with colorectal cancer and the anatomic distribution and characteristics of the tumour in a local Asian population. Methods: We conducted a review of consecutive patients who had undergone colonoscopy from 1999 to 2003 at the University of Malaya Medical Center, Kuala Lumpur, Malaysia. Results: Analysis was carried out on 3404 patients who underwent colonoscopy. A total of 228 patients (7%) were diagnosed with carcinoma. The mean age of diagnosis (+/- s.d.) was 64.4 +/- 13.1 years. The male to female ratio was 1.15. Polyps were noted in 470 patients (14%). Polyps detected concomitantly with a colorectal cancer were noted in 55 patients (2%). Four patients (0.1%) were diagnosed to have familial adenomatous polyposis coli. Of the 228 patients 209 (92%) had tumours at only one site whereas 19 (8%) had synchronous lesions. Tumours were mainly left sided [198 of 248 patients (80%)] with the majority located in the recto-sigmoid region. Detailed records of treatment were available only in 176 patients. A total of 147 of 176 patients (84%) underwent surgery and 50 (28%) also received adjuvant or palliative chemotherapy (28%). Seven of 154 patients (5%) were diagnosed to have stage A cancers, 64 (42%), stage B, 23 (15%), stage C and 60 (39%), stage D. Multivariate analysis using multiple logistic regression analysis showed that age >= 65 years (OR = 1.78; 95% CI: 1.35- 2.36) and Malay (OR = 2.09; 95% CI: 1.30-3.35) and Chinese (OR = 1.77; 95% CI: 1.77-2.69) race were significant independent predictive factors for colorectal cancer. Conclusions: The demography of colorectal cancer is different from western patients. Tumours were mainly left sided in our patients. However, no differences in anatomic location were found between races, men and women and younger and older age groups. Colorectal cancer presented in an advanced stage in the majority of patients.